Current Opinion in Nephrology and Hypertension

PURPOSE OF REVIEW: This review summarizes recent data supporting the concept that urinary microRNAs are a useful new class of biomarker. They may improve capacity to stratify patients with chronic kidney disease according to risk of progression, and may also inform about response to therapy. RECENT FINDINGS: MicroRNAs are present, stable and readily quantifiable in tissues and body fluids, including urine, and have widespread importance as regulators in the kidney...

PURPOSE OF REVIEW: Chronic kidney disease (CKD) is associated with symptoms that can significantly reduce the health-related quality of life (HRQOL) of patients. Patient-reported outcome and experience measures (PROMs and PREMs) may assist with the evaluation of HRQOL and quality of care from the patient perspective. This review focuses on evidence from recent studies exploring the role of PROMs and PREMs in the measurement of quality in CKD care. RECENT FINDINGS: PROMs are increasingly used in CKD research as measures of clinical effectiveness, whereas the current use of PROMs in routine clinical settings and PREMs in all settings is more limited...

PURPOSE OF REVIEW: This review describes the recent discoveries about a powerful electroneutral NaCl reabsorption mechanism in intercalated cells, and its regulation by an intrarenal metabolite paracrine, α-ketoglutartate, and the G-protein coupled receptor, Oxgr1. RECENT FINDINGS: The distal nephron fine-tunes sodium, chloride, potassium, hydrogen, bicarbonate and water transport to maintain electrolyte homeostasis and blood pressure. Intercalated cells have been traditionally viewed as the professional regulators of acid-base balance, but recent studies reveal that a specific population of intercalated cells, identified by the pendrin-transporter, have a surprising role in the regulation of salt balance...

PURPOSE OF REVIEW: Recent studies in the kidney have revealed that the well characterized tumor antigen mucin 1 (MUC1/Muc1) also has numerous functions in the normal and injured kidney. RECENT FINDINGS: Mucin 1 is a transmembrane mucin with a robust glycan-dependent apical targeting signal and efficient recycling from endosomes. It was recently reported that the TRPV5 calcium channel is stabilized on the cell surface by galectin-dependent cross-linking to mucin 1, providing a novel mechanism for regulation of ion channels and normal electrolyte balance...

PURPOSE OF REVIEW: Paracellular transport across the tight junction is a general mechanism for transepithelial transport of solutes in epithelia, including the renal tubule. However, why paracellular transport evolved, given the existence of a highly versatile system for transcellular transport, is unknown. RECENT FINDINGS: Recent studies have identified the paracellular channel, claudin-2, that is responsible for paracellular reabsorption of sodium in the proximal renal tubule...

PURPOSE OF REVIEW: The current review combines past findings with recent advances in our understanding of the homeostatic response to potassium imbalance. RECENT FINDINGS: Following the ingestion of a dietary potassium load, a combination of extrarenal and renal mechanisms act to maintain extracellular K+ within a tight window. Through hormonal regulation and direct K+ sensing, the nephron is ideally suited to respond to wide shifts in external K+ balance. Current evidence indicates that dietary K+ loading triggers a coordinated kaliuretic response that appears to involve voltage-dependent changes in sodium transport across multiple nephron segments, including the proximal tubule, medullary loop of Henle, and distal tubule...

PURPOSE OF REVIEW: AMP-activated protein kinase (AMPK) is a metabolic sensor that regulates cellular energy balance, transport, growth, inflammation, and survival functions. This review explores recent work in defining the effects of AMPK on various renal tubular epithelial ion transport proteins as well as its role in kidney injury and repair in normal and disease states. RECENT FINDINGS: Recently, several groups have uncovered additional functions of AMPK in the regulation of kidney and transport proteins...

PURPOSE OF REVIEW: Renal tubule excretion of calcium is carefully and complexly regulated. At the center of this process, parathyroid hormone (PTH) is the chief regulator of renal calcium reabsorption. This review outlines our current understanding of PTH's effects on renal tubular calcium transport, focusing on the more recent discoveries beyond its direct regulation of epithelial Ca channel transient receptor potential vanilloid 5 (TRPV5) and looking at its interaction with sodium transport and the hormones fibroblast growth factor 23 (FGF23) and klotho...

PURPOSE OF REVIEW: Antenatal Bartter syndrome (aBS) is a heterogenous disease resulting from defective ion transport in the thick ascending limb of the loop of Henle. Novel insights into the pathophysiology, as well as the recent identification of a novel genetic cause of aBS, merit an update on this topic. RECENT FINDINGS: In aBS, severe salt losing is further aggravated by defective salt sensing in the macula densa, where a reduced tubular salt concentration is perceived and glomerular filtration is increased instead of decreased...

PURPOSE OF REVIEW: Our aim was to review the rationale for the role of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) as renoprotective therapy in patients with and without diabetes. RECENT FINDINGS: SGLT-2i are antihyperglycemic agents, approved for treating type 2 diabetes to reduce glycosylated hemoglobin, type A1c. Primary glucoregulatory effects occur through selective inhibition of SGLT-2 at the renal proximal tubule promoting glucosuria leading to blood glucose lowering...

PURPOSE OF REVIEW: Tissue hypoxia is present in kidneys from diabetic patients and constitutes a central pathway to diabetic kidney disease (DKD). This review summarizes regulation of hypoxia inducible factor (HIF) and interventions towards the same for treatment of DKD. RECENT FINDINGS: In the hypoxic diabetic kidney, HIF activity and the effects of HIF signaling seem to be cell-specific. In mesangial cells, elevated glucose levels induce HIF activity by a hypoxia-independent mechanism...

PURPOSE OF REVIEW: Diabetic kidney disease (DKD) is one of the most common complications in diabetes mellitus and accounts for a large proportion of clinical nephrology practice. Studies have shown that the kallikrein-kinin system (KKS) may be involved in several pathogenic mechanisms that contribute to DKD, including oxidative stress, inflammatory cytokines, and profibrotic autacoids. This review focuses on recent research advance on the potential role of the KKS in the development of DKD and its clinical relevance...

PURPOSE OF REVIEW: Mesoamerican nephropathy (MeN) is an emerging pathophysiological entity of Chronic kidney desease (CKD) not related to traditional risk factors (diabetes and hypertension) that have caused thousands of deaths in Central America, mainly in sugarcane workers. The focus of this review is to discuss the risk factors and probable mechanisms involved in the initiation and progression of this devastating disease. RECENT FINDINGS: Frequent episodes of subclinical Acute kidney injury caused by repetitive heat stress, dehydration, and strenuous work have been regarded as the main risk factors for MeN...

PURPOSE OF REVIEW: This review discusses the role of molecular modifiers as inhibitors of kidney stone formation, drawing largely from in-vitro evidence while also citing relevant in-vivo studies. An emphasis is placed on physical observations of crystal growth inhibition, including mechanisms of action that focus predominantly on the literature of calcium oxalate and L-cystine. RECENT FINDINGS: The last decade has witnessed several breakthroughs in the identification of molecules with promise to curb kidney stone formation, as well as discoveries of the mechanisms by which these molecules (or combinations thereof) function as inhibitors of pathological crystal growth...

PURPOSE OF REVIEW: The prevalence of diabetic kidney disease (DKD) is increasing worldwide. Despite major therapeutic advances in the last decades in DKD, the current standard of care let many people progress to severe stages. Vasopressin secretion is increased in diabetes, and its potential role in the onset and progression of DKD is being re-investigated. RECENT FINDINGS: Recently, observational studies evidenced an association between surrogates of vasopressin secretion (daily fluid intake or urine volume, and plasma copeptin concentration) and chronic kidney disease in the community, but also specifically in type 1 and in type 2 diabetes...